Should specify the different exception class thrown for better logging

[alexjoybc]

jrcc-document-access-libs/jrcc-access-spring-boot-autoconfigure/src/main/java/ca/bc/gov/open/jrccaccess/autoconfigure/plugins/rabbitmq/RedisStorageService.java

Line 72 in eecc40f

public String getString(String key, String digest) throws DocumentMessageException {